ACOUSTIC SCATTERING BY 2 PARALLEL SLIGHTLY STAGGERED RIGID PLATES

In a recent paper Abrahams and Wickham [1] showed how to exactly solve the diffraction problem for two parallel semi-infinite plates which are arranged to form a duct. The edges of the plates are misaligned so that the geometry is asymmetric with respect to the central line of the duct. To evaluate the field it is first necessary to solve the integral equations derived in [1], and this can be accomplished analytically when the 'stagger' of the plates is small. In this paper we derive this analytic solution and use it to determine several terms in the asymptotic expansion of the velocity potential. The solution found by the method of matched asymptotic expansions is shown to be identical to this rigorous result. © 1990.